The present disclosure relates to systems and methods for compressed air energy storage (CAES), and more particularly to adiabatic CAES.
Oftentimes, electrical power consumed varies between peak hours and off-peak hours. For example, peak hours may include 8-12 daytime hours, and off-peak hours may include the remaining 12-16 hours of the day and/or night. CAES is a way to store energy generated during off-peak hours for use during peak hours.
In conventional CAES systems, excess power from an electrical grid is used to power an electric motor that drives a compressor. Gas (usually atmospheric air) compressed by the compressor is cooled and stored in a cavern at a high pressure. During peak hours, the compressed gas is drawn from the cavern, heated, and supplied to a combustion system that further expands the hot gas across a turbine. The energy from the heated compressed gas drives the turbine, which is coupled to and drives an electrical generator. The electrical generator generates electrical power that is re-supplied to the electrical grid. In the foregoing system, known as a “diabatic” CAES system, the heat energy from the gas output from the compressor is transferred out of the system, and additional energy is used to re-heat the compressed gas that is fed to the turbine.
It is therefore desirable to find improved CAES systems and methods offering higher efficiencies and reduced cost.